Thanks to you too for always making such great videos. ^_^
I think a lot of people will be happy to see ‘ASCENDEAD MASTER’ subbed, the song seems to be very popular…it’s actually one of my most viewed posts of all time. 0_0

You know, I’ve been wondering about which is correct for a while because it’s not 100% clear. The verb is transitive, which means someone is doing the sinking, but there’s no を to indicate the object. Looking at it again, I think the most logical interpretation is that god sank the people.

Well, not quite. You can’t tell that by the wa/ga distinction alone because even if it was wa, depending on the context (or lack thereof) “God” could still be the subject.

Rather I think it’s the verb form that matters. If it were ‘Kami ga shizumareta’ it would be ‘God was sunk’, but ‘Kami ga shizumeta’ means “God sank” as in God is the one doing the sinking (since it’s transitive).

When talking about submerging oneself you’d probably use shizumu with wa/ga, and shizumeru only with wo, therefore the interpretation that seems to make the most sense is that wa is being used contrastingly to mark the subject (God) who is doing the action (sinking) to the other subject in the sentence, and the repetition of this second subject (the people) is dropped.